Ink cartridge for ink jet printer

ABSTRACT

An ink cartridge for an ink jet printer is provided with a container having at least a first wall. An ink supply port is formed through the first wall for supplying ink to the exterior of the container. An ink chamber and an ink supply chamber are formed by a membrane valve seat made of an elastic thin membrane and formed with a through hole therethrough. A valve body is positioned opposing the through hole formed in the membrane valve seat, the valve body and membrane valve seat adjacent said through hole formed therein being maintained selectively in contact by a pressure difference between said ink chamber and said ink supply chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of copending U.S. patent applicationSer. No. 09/749,325, filed on Dec. 27, 2000, which is a continuation ofU.S. patent application Ser. No. 09/460,363, filed Dec. 13, 1999, nowU.S. Pat. No. 6,193,364, which is a continuation of application Ser. No.08/548,574, filed Oct. 26, 1995, now U.S. Pat. No. 6,000,788.

BACKGROUND OF THE INVENTION

The present invention relates generally to an ink cartridge and moreparticularly to an ink cartridge which is suitable for being mounted ona carriage for carrying an ink jet type recording head.

An ink jet recording apparatus such as an ink jet printer comprises anink jet type recording head carried on a carriage in which pressure isapplied to a pressure generating chamber. This chamber is maintained influid communication with a common ink tank on one side of the chamberand a nozzle opening on an other. Ink droplets are discharged from thenozzle opening upon the generation of pressure in the chamber. An inkcartridge comprising either the common ink tank or the common ink tankand a plurality of chambers and nozzle openings may be carried on thecarriage for supplying the recording head with ink. This ink cartridgeis constructed so that ink droplets are discharged onto a recordingmedium in response to printing data as the carriage is reciprocallymoved.

Since the nozzle opening of the recording head is located at a positionlower than the ink level in the ink cartridge, fluid pressure of the inkacts on the nozzle opening. A porous material is generally contained inthe ink cartridge so that surface tension caused by the porous materialallows the pressure inside the ink cartridge to be slightly lower thanthat at the nozzle opening in order to prevent ink from oozing out fromthe nozzle opening.

However, as ink is gradually consumed during printing operations and asmaller amount of ink remains absorbed in the porous material, thesurface tension caused by the porous material becomes larger and makesit difficult to supply ink to the recording head. Thus, all inkcontained in the cartridge will not be completely consumed.

Also, because of the porous material contained in the ink cartridge, theamount of ink stored in the ink cartridge is less than the volume of theink cartridge by the actual total volume of the porous material. Tocompensate for the decreased amount of ink in a cartridge employingporous material, a larger ink cartridge is required than would be if theporous material were not employed in order to hold the same amount ofink.

To solve the problem mentioned above, an ink cartridge for an ink jetrecording head, for example, as shown in U.S. Pat. No. 4,677,447 (basedupon JP-A-62-23 1759), has been proposed. This patent shows an ink tankthat is separated into two chambers by a wall formed with a through holein a lower portion thereof. Ink is provided to the recording head fromthe first chamber. An umbrella check valve is movably arranged in thethrough hole. When the ink pressure on the ink head is decreased byexpulsion of ink from the chamber, the umbrella check valve is opened todischarge the ink from the into to the cavity, and it is then suppliedto the recording head from the first chamber into the second chamber,and it is then supplied to the recording head from the second chambercavity.

According to the above-mentioned ink cartridge, a porous material neednot be contained in the cartridge, so that a larger amount of ink can besubstantially stored in the ink cartridge. However, use of the umbrellacheck valve raises another problem, since its offset amount is too largeto finely adjust the amount of ink to be supplied to the recording head.Thus, fluctuations in the amount of ink supplied are caused and theprinting quality is degraded.

In addition, since the ink in the first chamber is completely blockedfrom the recording head when the umbrella check valve is closed, if somechange in environmental factors or temperature causes the volume of inkin the second chamber to increase as little as two to five percent, thepressure in the first chamber could increase and break the seal on aconnection port which couples the ink cartridge to the recording head.The ink could then leak from the broken seal. Further, when thecartridge is mounted on the recording head, this increased pressure actson the recording head whereby negative pressure cannot be maintainedbetween the recording head and the ink tank, and thus ink could leakfrom the recording head.

Furthermore, the umbrella check valve is maintained in a closed statewith a pressure difference of approximately 50 mmAq in order to ensure astable supply of ink to the recording head. However, since this valveclosing force is small, the umbrella check valve may open in response toa swinging motion of ink in the ink tank due to the movement of thecarriage resulting in temporary pressure differences against the valvefrom the movement. Thus, stable printing may not be provided.

Additionally, if air enters a recording head while ink is being suppliedthereto, the pressure for discharging ink droplets may be absorbed bythe air bubble occurring within an ink passage of the recording head.Thus, defective printing may arise when the ink cartridge is exhausted.This problem may also arise if an ink cartridge is removed from arecording head if the ink is not depleted.

Accordingly, it is desirable to provide an ink cartridge which iscapable of reliably supplying a recording head with ink in response to aminute pressure difference between the recording head and the inkcartridge, while maintaining negative pressure suitable for printingbetween the recording head and the ink cartridge, without beinginfluenced by any swinging motion of ink contained therein due to themovement of a carriage upon which the recording head is mounted, and isalso capable of preventing ink from leaking from an ink supply port ofthe cartridge leading to the recording head, or leaking from therecording head, due to temperature or other atmospheric changes:

Additionally, it is desirable to provide an ink cartridge which canprevent air from being drawn into the recording head at the time ink inthe ink cartridge is exhausted, or if the ink cartridge is removedbefore all of the ink is depleted.

SUMMARY OF THE INVENTION

Generally speaking, in accordance with the invention, an ink containerhaving an ink supply port formed in one of its walls is separated intotwo portions by a membrane valve seat made of an elastic thin membraneand formed with a through hole in a central portion thereof. Themembrane forms an ink chamber in the portion of the ink container notadjacent the ink supply port and an ink supply chamber in the portion ofthe ink container adjacent the ink supply port. A valve body is arrangedat a position opposite the through hole such that the membrane valveseat is urged to abut the valve body by a pressure difference betweenthe ink chamber and the ink supply chamber, thereby selectively sealingthe through hole.

The membrane valve seat receives a pressure difference over a wide areathereof to open a passage from the ink chamber to the ink supply chamberin response to the consumption of a small amount of ink from the inksupply chamber. Thus, the ink can be discharged to a recording headwithout resulting in excessive negative pressure being imparted on therecording head. Also, if the pressure inside the ink supply chamberincreases due to a temperature rise, other environmental factors or thelike, the membrane valve seat is responsive to this increased pressurein the ink supply chamber and releases an increased portion of ink fromthe ink supply chamber to the ink chamber, thereby preventing ink fromleaking from the recording head. Further, the membrane valve seat ismaintained in close contact with the valve body through its ownelasticity to reliably prevent the valve member from bouncing orvibrating due to the movement of the carriage. The ink container may bein the form of an ink cartridge removably mounted on the recording head.

Accordingly, it is an object of this invention to provide an improvedink cartridge capable of reliably supplying ink to a recording head.

Another object of the invention is to provide an improved ink cartridgecapable of regulating the pressure imparted to the recording head.

A further object of the invention is to provide an improved inkcartridge capable of regulating the pressure imparted to the recordinghead and keeping ink from leaking even if temperature changes or otherenvironmental changes cause a change in pressure in the cartridge.

Yet another object of the invention is to provide an improved inkcartridge which prevents air from being drawn into the recording head ifthe ink in the cartridge is exhausted, or if the ink cartridge isremoved before all of the ink is exhausted.

Still other objects and advantages of the invention will in part beobvious and will in part be apparent from the specifications anddrawings.

Additionally, the invention accordingly comprises the features ofconstruction, combinations of elements, and arrangements of parts whichwill be exemplified in the constructions hereinafter set forth, and thescope of the invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the invention, reference is had to thefollowing description taken in connection with the accompanyingdrawings, in which:

FIG. 1 is a cross-sectional view of an ink tank cartridge constructed inaccordance with a first embodiment of the invention;

FIGS. 2A and 2B respectively are fragmentary cross-sectional views ofthe ink tank cartridge of FIG. 1 showing how the membrane valve seat andthe valve body operate when the ink cartridge is mounted on a recordinghead;

FIG. 2C is a cross-sectional view of the ink tank cartridge of FIG. 1showing the valve body when the ink cartridge is supplied with ink;

FIG. 3 is a graph representing the relationship between a dischargingamount of ink and the fluid pressure value of the ink cartridge of FIG.1;

FIG. 4 is a fragmentary cross-sectional view of an ink tank cartridgeconstructed in accordance with a second embodiment of the inventionshowing the ink supply chamber and its surroundings;

FIG. 5 is a cross-sectional view of an ink tank cartridge constructed inaccordance with a third embodiment of the invention;

FIGS. 6A and 6B respectively are fragmentary cross-sectional views ofthe ink tank cartridge of FIG. 5 showing how the membrane valve seat andthe valve body operate when the ink cartridge is mounted on a recordinghead;

FIG. 6C is also a cross-sectional view of the ink tank cartridge of FIG.5 showing the valve body when the ink cartridge is supplied with ink;

FIG. 7 is a fragmentary cross-sectional view of an ink tank cartridgeconstructed in accordance with a fourth embodiment of the inventionshowing the ink supply chamber and its surroundings;

FIG. 8 is a fragmentary cross-sectional view of an ink tank cartridgeconstructed in accordance with a fifth embodiment of the inventionshowing the ink supply chamber and its surroundings;

FIG. 9 is a fragmentary cross-sectional view of an ink tank cartridgeconstructed in accordance with a sixth embodiment of the inventionshowing the ink supply chamber and its surroundings;

FIG. 10 is a fragmentary cross-sectional view of an ink tank cartridgeconstructed in accordance with a seventh embodiment of the inventionshowing the ink supply chamber and its surroundings;

FIG. 11 is a cross-sectional view showing an ink supply port of an inkcartridge constructed in accordance with an eighth embodiment of theinvention;

FIGS. 12A and 12B are cross-sectional views showing an ink supply portof an ink cartridge constructed in accordance with a ninth embodiment ofthe invention, FIG. 12A showing the ink supply port not mounted on arecording head and FIG. 12B showing the ink supply port mounted on arecording head; and

FIG. 13 is a schematic view showing an ink supply system of an ink jettype recording apparatus to which the embodiments of the invention canbe applied.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 13 is a schematic view showing an ink supply system of an ink jettype recording apparatus to which the present invention can be applied.

A print head unit 101 of an ink jet type is connected to an ink tank 103through a connecting member 102. Ink is supplied from ink tank 103 toprint head unit 101 through a hollow needle 102 a and an ink supplypassage 102 b of connecting member 102, so that print head unit 101emits droplets of ink in accordance with print signals.

The apparatus shown in FIG. 13 also includes a cap member 104 disposedin a non-printing area. Cap member 104 is displaceable into an abuttingposition against the nozzle plate of print head unit 101 by a drivemechanism (not shown), for preventing the nozzle openings from drying.Cap member 104 is connected through a tube 108 to a suction pump 105which is operated by a control device 106 to suction ink from print headunit 101 through cap member 104. The apparatus shown in FIG. 13 is alsoprovided with an effluent tank 107 connected to an outlet port ofsuction pump 105 through a tube 109.

The recording head may be of any structure described in European PatentPublication Nos. 581,531; 609,863; 584,823.

Referring to FIG. 1, a first embodiment of the invention is depictedwherein a container constituting an ink cartridge body, indicatedgenerally at reference numeral 1 is formed with a first wall 1 a with anink supply port 2 formed therein, into which an ink supply needle of arecording head (not shown) may be inserted. The space inside container 1is separated into an ink chamber 4 and an ink supply chamber 5 by amembrane valve seat 3, described hereinafter. Membrane valve seat 3 ismade of an elastic membrane, such as a rubber membrane, polymericelastomer membrane or the like, having a resistance to ink, and formedwith a membrane through hole 6 in a central portion thereof. Membranevalve seat 3 is placed on a step 7 formed in a lower portion ofcontainer 1. Membrane valve seat 3 is maintained in a stretched state bya valve assembly 9 which engages and holds the periphery of membranevalve seat 3 against step 7.

A valve body 8 is vertically movably inserted into a valve through hole10 formed through valve assembly 9. Valve body 8 has a width thatensures the formation of a gap between valve assembly 9 and valve body 8through which ink flows, and a length slightly larger than the thicknessof valve assembly 9. In a normal state, when cartridge 1 is notconnected to a recording head undergoing a printing operation, valvebody 8 has its lower end placed in elastic contact with membrane valveseat 3 by a valve body support member 11 so as to close the membranethrough hole 6 of membrane valve seat 3. The lower end of valve body 8is formed with a curved periphery to form a better seal with membranevalve seat 3. Valve assembly 9 is formed with an ink passage 15 in thesurface thereof facing away from ink supply port 2 and communicating tovalve through hole 10 for directing ink thereto.

Valve body support member 11 is arranged on and secured at its peripheryto the surface of valve assembly 9 on the opposed side of valve assembly9 to membrane valve seat 3, in a stretched state in order to maintainvalve body 8 in elastic contact with membrane valve seat 3, as well asto prevent valve body 8 from lowering below a predetermined position.Valve body support member 11 is made of a similar material to that ofmembrane valve seat 3, and is formed with a support member through hole12 therein forming ink passage 15. Also, valve body support member 11supports a top portion 8 a of valve body 8 adjacent but spaced fromsupport member through hole 12. In this embodiment, the upper end ofvalve body 8 is formed with annular peripheral groove 8 b for receivingthe periphery of a mounting aperture 11 a in valve support member 11 anda head 8 a shaped both to be forced through mounting aperture 11 a byelastic deformation thereof due to its rounded top end, and to retainthe valve body on the valve body support membrane when mounted thereon.

Preferably, membrane valve seat 3, valve body support member 11, andvalve body 8 are assembled with and fixed to valve assembly 9 prior tothe final construction of container 1, and are incorporated intocontainer 1 by placing the entire assembly on step 7 of container 1 atone time.

Container 1 has its upper end closed by a lid member 13 having anatmosphere communicating hole 14 formed therethrough. On the side of lidmember 13 facing the inside of ink chamber 4, lid member 13 is formedwith a recess 30 surrounding atmosphere communicating hole 14, acommunicating port 32 positioned a predetermined distance away fromrecess 30, and a narrow groove 31 constituting a capillary channel formaintaining recess 30 and communicating port 32 in fluid communication.A flexible membrane 33 is arranged over recess 30 and groove 31 in sucha loose state that flexible membrane 33 is maintained a small distanceaway from communicating hole 14 when lid member 13 is placed oncontainer 1, while one wall of the capillary channel of groove 31 isdefined by flexible membrane 33.

In this embodiment, if container 1 is positioned (for example, tilted orturned upside down) to bring ink in ink chamber 4 into contact with lidmember 13, flexible membrane 33 receives the pressure of the ink and ismoved towards lid member 13. Flexible membrane 33 then comes intocontact with a protrusion 14 a defined by recess 30 around atmospherecommunicating hole 14, so that atmosphere communicating hole 14 isclosed to prevent the ink from leaking therethrough.

When ink supply port 2 is penetrated by an ink supply needle of therecording head (not shown) carried on a carriage (the ink supply portbeing normally sealed by an ink impermeable closure (not shown)pierceable by the needle in a conventional manner), ink supply chamber 5is placed in fluid communication via this ink supply needle with therecording head. In this state, flexible membrane 33 of lid member 13 ismaintained in a hanging position away from lid member 13 so as to openatmosphere communication hole 14 because of gravity or other pressuredifference. Thus, ink chamber 4 communicates with the atmosphere throughopen atmosphere communicating hole 14, recess 30, groove 31, andcommunicating port 32.

As is shown in FIGS. 2A, 2B and 2C, in the cartridge constructed in thismanner, when printing is started and the recording head discharges inkdroplets onto a recording medium or the like, ink in ink supply chamber5 flows through ink supply port 2 into the recording head, whereby thepressure inside ink supply chamber 5 gradually decreases. In response tothe decreased pressure inside ink supply chamber 5, membrane valve seat3 receives pressure from ink chamber 4 and expands in the directiontoward ink supply port 2, by virtue of its elasticity, in the form of anessentially spherical surface having a radius R. At this time, sincevalve body 8 moves in conjunction with membrane valve seat 3 (FIG. 2A),ink contained in ink chamber 4 is prohibited from flowing into inksupply chamber 5 which in turn prevents the pressure inside ink supplychamber 5 from increasing excessively, while also preventing thepressure inside ink supply chamber 5 from decreasing excessively. Inthis manner, the pressure on the recording head is maintained atconstant negative pressure with respect to the ink chamber 4.

As more ink is consumed by the recording head during a printingoperation, membrane valve seat 3 is further elastically expanded towardink supply port 2. Valve body 8 is prevented from lowering below apredetermined position by valve body support member 11, so that valvebody 8 is separated from membrane valve seat 3 by a very narrow gap 6 a(FIG. 2B). In this state, ink in ink chamber 4 passes through supportthrough hole 12, passage 15, valve through hole 10 and narrow gap 6 aformed between valve body 8 and membrane valve seat 3, and flows throughmembrane through hole 6 into ink supply chamber 5.

When the inflow of the ink causes the pressure inside ink supply chamber5 to slightly increase, membrane valve seat 3 moves back toward valvebody 8 by its elasticity and elastically contacts with valve body 8,whereby narrow gap 6 a and membrane through hole 6 are closed by thelower surface of valve body 8. This prohibits ink from flowing from inkchamber 4 into ink supply chamber 5. As a result, the pressure at theink supply port is maintained at a constant level irrespective of theamount of ink contained in ink chamber 4.

Each time the pressure inside ink supply chamber 5 slightly decreasesbecause of ink consumption during a printing operation, membrane valveseat 3 slightly expands toward ink supply port 2 to form a gap betweenmembrane valve seat 3 and valve body 8, through which ink from inkchamber 4 flows into ink supply chamber 5. In this manner, membranevalve seat 3, made of an elastic membrane, is brought into contact withand separated from valve body 8 in accordance with the consumption ofink during printing. Thus, by setting the elasticity of membrane valveseat 3 at an appropriate predetermined magnitude, it is possible toremarkably reduce the difference in pressure between the time an inksupply procedure will begin and end, as well as to discharge all ink inink chamber 4 to the recording head so that none of the ink will bewasted.

If the ambient temperature rises while printing is not being performed,the pressure inside ink supply chamber 5 will increase. This increase inpressure may also be caused by changes in a number of otherenvironmental factors. In response to this increased pressure, membranevalve seat 3 moves toward ink chamber 4 which is open to the atmosphere.This prevents the pressure inside ink supply chamber 5 from increasing,thus maintaining appropriate negative pressure between ink chamber 4 andrecording head irrespective of temperature rise or pressure increase. Itis therefore possible to prevent ink from leaking from the recordinghead due to an increase in pressure.

In a preferred embodiment, membrane valve seat 3 is formed of a rubber.membrane having a thickness of 0.04 mm and an effective diameter, i.e.,an elastically deformable region of 20 mm. A lower limit position ofvalve body 8 is designed such that the radius R of the spherical surfaceis 26 mm immediately before ink flows out, i.e., in a critical statewith valve body 8. Reference is now made to FIG. 3, which is a graphwhich depicts the change in fluid pressure value of the ink cartridgeaccording to the invention. It can be understood from FIG. 3 that evenif a large amount of ink, for example, five grams. per minute of ink, issupplied, the increase in fluid pressure value is small. Thus, ink canbe smoothly supplied to the recording head even if a large amount of inkis consumed by the recording head without imparting excessive negativepressure on the recording head.

During the manufacturing and ink filling process, a negative pressure isapplied to ink chamber 4 to exhaust air from cartridge 1. With inksupply port 2 being closed by a filling seal 16, ink chamber 4 initiallyachieves a lower pressure than ink supply chamber 5. Thus, as shown inFIG. 2C, valve body 8 moves toward ink chamber 4 against the elasticforce of valve body support member 11 to form a filling gap 12 a betweenmembrane valve seat 3 and valve body 8, so that all air can be exhaustedfrom the entire cartridge 1 including ink chamber 4 and ink supplychamber 5, irrespective of the existence of membrane valve seat 3 andvalve body 8. This permits the entire cartridge 1, including ink supplychamber 5, to be filled with ink.

Reference is now made to FIG. 4 which depicts an ink cartridge 200constructed in accordance with a second embodiment of the invention,like elements being designated by like reference numerals. In thissecond embodiment, valve body 8 is provided with a flat positioningpiece 35 fixed thereto on the side thereof facing valve body supportmember 11, in the region of valve through hole 10, which abuts the upperperipheral surface of valve body 8 when the lower surface of valve body8 is brought into contact with membrane valve seat 3. When valve body 8abuts membrane valve seat 3, positioning piece 35 is maintained incontact with the upper surface of valve assembly 9 and the periphery ofvalve body 8, and valve body 8 is supported by valve assembly 9 tomaintain its posture as vertical as possible. Thus, membrane throughhole 6 of membrane valve seat 3 can be reliably closed by valve body 8even if cartridge 200 suffers from vibrations due to the movement of thecarriage or the like.

Reference is now made to FIG. 5 which depicts an ink cartridge 300constructed in accordance with a third embodiment of the invention, likeelements being designed by like reference numerals. In this embodiment avalve body 20 is inserted into a valve body accommodating chamber 9 aformed in valve assembly 9′ with spring 21 positioned to urge valve body20 toward ink supply port 2. A lower limit position of valve body 20 isdefined by a laterally outwardly extending positioning piece 36 formedon the upper end of valve body 20 abutting a laterally inwardlyextending protrusion 9 b formed in a lower portion of valve bodyaccommodating chamber 9 a. Also, as is shown in FIG. 5, ink chamber 4 isselectively maintained in fluid communication with ink supply chamber 5via through holes 22 and 23, through hole 22 communicating directlybetween ink chamber 4 and valve body accommodating chamber 9 a, whichthrough hole 22 communicates directly between ink chamber 4 and thespace between membrane valve seat 3 and has a laterally extendingsurface groove 23 a formed on the side of valve assembly 9′ facing saidmembrane valve seat 3 extending between through hole 23 and valve bodyaccommodating chamber 9 a.

In this third embodiment, as is shown in FIGS. 6A, 6B and 6C, membranevalve seat 3, in response to decreased pressure inside ink supplychamber 5, receives pressure from ink chamber 4 and expands towardsupply port 2, by virtue of its elasticity, in the form of anessentially spherical surface having a radius R. Thus, since valve body20 moves in conjunction with membrane valve seat 3 by the resilientforce of spring 21, and positioning piece 36 abuts protrusion 9 b tomaintain valve body 20 in a vertical posture (FIG. 6A), ink isprohibited from flowing from ink chamber 4 into ink supply chamber 5while preventing the pressure inside ink supply chamber 5 fromdecreasing excessively. In this manner, membrane valve seat 3 abutsvalve body 20 irrespective of any vibrations or swinging motion of thecartridge due to the movement of the carriage, so that ink pressure onthe recording head is maintained at constant negative pressure withrespect to ink chamber 4.

As more ink is consumed by the recording head during a printingoperation, membrane valve seat 3 is further expanded toward ink supplyport 2. Valve body 20 is prevented from lowering below a predeterminedposition by protrusion 9 b of valve accommodating chamber 9 a, so thatvalve body 8 is separated from membrane valve seat 3 by very narrow gap6 a (FIG. 6B). In this state, ink in ink chamber 4 passes through narrowgap 6 a formed between valve body 20 and membrane valve seat 3 and flowsthrough membrane through hole 6 into ink supply chamber 5.

When the inflow of the ink causes the pressure inside ink supply chamber5 to slightly increase, membrane valve seat 3 moves back toward valvebody 20 by its elasticity and elastically contacts with valve body 20,whereby narrow gap 6 a and membrane through hole 6 are closed by thelower surface of valve body 20. This prohibits ink from flowing from inkchamber 4 into ink supply chamber 5. As a result, the pressure at inksupply port 2 is maintained at a constant level irrespective of theamount of ink contained in the ink chamber 4.

During the manufacturing and ink filling process, a negative pressure isapplied to ink chamber 4 to exhaust air from cartridge 300. With inksupply port 2 being closed by filling seal 16, ink chamber 4 achieves alower pressure than ink supply chamber 5. Thus, as shown in FIG. 6C,valve body 20 moves toward ink chamber 4 against the force of spring 21to form a filling gap 12 a between membrane valve seat 3 and valve body20, so that all air can be exhausted from the entire cartridge 300,irrespective of the existence of membrane valve seat 3 and valve body20. This permits the entire cartridge 300 including ink supply chamber 5to be filled with ink.

In the foregoing third embodiment, an elastic member (spring 21) forbringing valve body 20 into contact with membrane valve seat 3 isincorporated in valve assembly 9′. Alternatively, in a fourthembodiment, like elements being designated by like reference numerals,an ink cartridge body 400 may be formed with a valve body 37, as shownin FIG. 7, which may be formed in a mushroom shape, such that a capportion 37 a functions as a positioning piece and as a stopper, and aspring 38, mounted at its periphery to the top surface of valve assembly9″, may be used to urge the top of valve body 37 toward membrane valveseat 3. Since valve body 37 and spring 38 can be mounted from theoutside of valve assembly 9″, the assembling work of the ink tankcartridge can be simplified. A through hole 9 c is formed in valveassembly 9″ communicating between ink chamber 4 and the space betweenthe lower surface of valve assembly 9″ and membrane valve seat 3.

Reference is now made to FIG. 8 which depicts an ink cartridge 500constructed in accordance with a fifth embodiment of the invention, likeelements being designated by like reference numerals. While in theforegoing embodiments, the spring is arranged above the valve body, itis apparent that similar effects can be produced when a container 500 isseparated into an ink chamber 42 and an ink supply chamber 43 by apartition 41 formed with a partition through hole 41 a. Ink supplychamber 43 houses a membrane valve seat 44 and a valve body 46comprising an elongated portion 46 b extending through a membranethrough hole 45 and head portion having a spherically formed lowersurface 46 a for sealing membrane through hole 45 formed throughmembrane valve seat 44. Elongated portion 46 b extends from andperpendicular to lower surface 46 a and penetrating membrane throughhole 45 of membrane valve seat 44. Elongated portion 46 b extendsthrough and is supported on a spring 47 which always urges elongatedportion 46 b, and therefore valve body 46, in the direction of an inksupply port 49 and a guide hole 48, which receives the lower end ofsupport member 46 b to position valve body 46 in a vertical postureformed in a wall of the cartridge as shown in FIG. 8. Guide hole 48 isdefined by an upwardly projecting annular wall 43 a formed in a bottomwall 49 a of ink cartridge 500.

According to this fifth embodiment, since valve body 46 is always urgedtoward wall 49 a, in which ink supply port 49 is formed, by spring 47 tomaintain a stable posture, irrespective of any force generated by ink,ink can be stably supplied to the recording head irrespective of anyvibrations or swinging motion of ink in cartridge 500 due to themovement of the carnage. In this embodiment, similar to those describedabove, when the pressure below membrane valve seat 44 is decreased dueto ink being consumed during printing, membrane valve seat 44 movestoward ink supply port 49, thereby maintaining the pressure below valveseat 44. When elongated portion 46 b engages the bottom of guide hole48, the movement of valve body 46 is stopped. Thereafter, any additionalconsumption of ink moves membrane valve seat 44 away from lower surface46 a of support member 46, thereby exposing a membrane through hole 45,and allowing ink to pass therethrough.

Reference is now made to FIG. 9 which depicts ink cartridge 600constructed in accordance with a sixth embodiment of the invention, likeelements being designated by like reference numerals. A levelstabilizing membrane 50 is made of a soft porous membrane or latticemembrane which can move in conjunction with membrane valve seat 3 isprovided. A porous member through hole 51 is formed through a regionopposite valve body 8 of stabilizing membrane 50, and a lower endportion of valve body 8 is fit into porous member through hole 51.Stabilizing membrane 50 has its periphery secured to valve assembly 9and a central portion thereof secured to valve body 8.

When the pressure inside ink supply chamber 5 decreases as more ink isconsumed during a printing operation, membrane valve seat 3 separatesfrom valve body 8 so that ink in ink chamber 4 flows through porousmember through hole 51 of level stabilizing membrane 50 into ink supplychamber 5.

After an additional amount of ink has been consumed during printingoperations and the level of ink in ink chamber 4 has been reduced to alevel lower than the position of valve assembly 9, the ink in inkchamber 4 may violently swing near valve body 8 due to the movement ofthe carriage. However, since the ink passes through membrane throughhole 6 of membrane valve seat 3 after fluctuations in pressure of theink have been suppressed by level stabilizing membrane 50 as much aspossible, the ink pressure on the recording head is maintained at aconstant level irrespective of the amount of ink remaining in inkchamber 4.

While in a number of the foregoing embodiments, an elastic member (valvebody support member 11) is used to elastically maintain contact betweenthe valve body 8 and membrane valve seat 3, the elastic member forelastically contacting valve body 8 with membrane valve seat 3 may beunnecessary if the elastic force of membrane valve seat 3 is activelyutilized.

Reference is now made to FIG. 10 which depicts an ink cartridge 700constructed in accordance with a seventh embodiment of the invention,like elements being designed by like reference numerals. This seventhembodiment does not require an elastic member for elastically urging avalve body to maintain contact with a membrane valve seat. As shown inFIG. 10, a membrane valve seat 24 is formed with a membrane through hole25 formed therein in a region opposing a valve body 28, hereinafterdescribed, and has its periphery secured by a valve assembly 27. Valvebody 28 is unmovably fixed to valve assembly 27 in a positionperpendicular thereto. Ink chamber 4 is selectively maintained in fluidcommunication with ink supply chamber 5 via a communicating hole 29 inthe form of a radial slit extending from valve body 28. When a pressuredifference between ink chamber 4 and ink supply chamber 5 is equal to orless than a predetermined value, membrane valve seat 24, through its ownelasticity, brings membrane through hole 25 into contact with valve body28 to stop the outflow of ink from ink chamber 4 to ink supply chamber5.

On the other hand, if the pressure inside ink supply chamber 5decreases, membrane valve seat 24 extends toward ink supply port 2 inthe form of a spherical surface, whereby membrane through hole 25 isremoved from contact with valve body 28, and accordingly ink flows fromink chamber 4 into ink supply chamber 5 via membrane through hole 25.After a sufficient amount of ink has been supplied to ink supply chamber5 to raise the pressure inside ink supply chamber 5, membrane valve seat24 elastically contacts with valve body 28, against the pressuredifference between ink chamber 4 and ink supply chamber 5, to stop theoutflow of ink from ink chamber 4 to ink supply chamber 5.

Reference is now made to FIG. 11 which depicts an ink cartridgeconstructed in accordance with an eighth embodiment of the invention,like elements being designated by like reference numerals. The inkcartridge of this eighth embodiment prevents air from entering arecording head at the time the recording head has depleted all of theink in the ink cartridge. In a connecting region between an ink supplyport 52 and an ink supply chamber 53, a downwardly tapered conical valveseat 54 is formed. A spherical floating valve 55, which floats by afloating force produced by the buoyancy of spherical floating valve 55,is accommodated in conical valve seat 54. Further, the upper end of theconical valve seat 54 is covered with a valve retention plate 56, madeof an ink transmissible material such as a screen, to complete ashielding valve. In FIG. 11, a membrane valve seat 57 is also arrangedin selectable contact with a valve body 58 for controlling the flow ofink thereto from an ink chamber (not shown).

When the ink cartridge is mounted on the recording head, floating valve55 floats upward and is retained against valve retention plate 56 by afloating force to open ink supply port 52 through which ink is suppliedto the recording head. As ink in the cartridge is consumed duringprinting operations, the level of ink in the cartridge is reduced in thevicinity of ink supply port 52. Floating valve 55 looses its floatingforce because of the absence of ink, and therefore comes into contactwith valve seat 54 to close ink supply port 52 (as indicated by thebroken line in FIG. 11). Even if printing is continued with the almostexhausted cartridge, the closed ink supply port 52 prohibits air fromentering the recording head, thus preventing defective printing.

Generally, an ink cartridge, once mounted on a recording head, is notremoved until ink contained in the ink chamber is depleted. However, theink cartridge may be removed from the recording head by an erroneousmanipulation. If a once mounted cartridge is removed from the recordinghead, ink supply port 52 is open to the atmosphere and may allow air toenter the ink supply chamber and the ink chamber, which may adverselyaffect the flow of ink during the recording operation.

Reference is now made to FIGS. 12A and 12B which depict an ink tankcartridge constructed in accordance with a ninth embodiment of thepresent invention, like elements being designated by like referencenumerals. As shown in FIGS. 12A and 12B, the ink cartridge of this ninthembodiment prevents air from entering the cartridge if the ink cartridgeis removed before it is depleted. A telescopical valve body 60 isarranged in an ink supply port 61, and is formed with an ink supplyneedle fitting hole 62 in its lower portion into which an ink supplyneedle 70 may be removably fitted. Valve body 60 is also formed with acommunicating hole 64 for connecting an ink supply chamber 63 with inksupply needle fitting hole 62 when valve body 60 moves to an upwardlimited position.

In this embodiment, before insertion of ink supply needle 70, as shownin FIG. 12A, valve body 60 which is formed with a radially extending,elastic periphery 60 a, is maintained in elastic contact with a bottomsurface 63 a of ink supply chamber 63 by its elasticity to reliablyprevent the outflow of ink from ink supply chamber 63.

When ink supply needle 70 is inserted into fitting hole 62, valve body60 is separated from bottom surface 63 a of ink supply chamber 63 andextends to the upward limited position, while communicating hole 64 isexposed to ink supply chamber 63 (FIG. 12B). This causes ink supplychamber 63 to be placed in fluid communication with an ink passage 70 aof ink supply needle 70 through communicating hole 64, and a needlecommunicating hole 70 b, whereby ink in ink supply chamber 63 flows intoink supply needle 70 and is consequently supplied to the recording head.

When the ink cartridge mounted on the recording head is removed, valvebody 60 moves toward the bottom of FIG. 12A to close ink supply port 61and hence ink supply chamber 63. This prevents the outflow of ink fromink supply chamber 63 as well as the entrance of air into ink supplychamber 63.

According to the present invention as described above, a containerformed with an ink supply port in one of its walls is separated by amembrane valve seat made of an elastic thin membrane and formed with athrough hole in the central portion thereof. An ink chamber is formed inthe portion of the cartridge not adjacent the ink supply port, and anink supply chamber is formed in the portion of the cartridge adjacentthe ink supply port, and a valve body is positioned in opposition to thethrough hole. The membrane valve seat receives a pressure differenceover a large area thereof because of the consumption of ink and allowsink to flow from the ink chamber in response to a small amount ofconsumed ink. Thus, the recording head can be supplied with ink withoutimparting excessive negative pressure on the recording head, and ink inthe ink chamber can be discharged to the recording head without waste.Moreover, if the ambient temperature rises greatly or otherenvironmental factors cause the pressure to increase while printing isnot being performed, the membrane valve body displaces toward the inkchamber to release the pressure increased by the pressure rise insidethe ink supply chamber communicating with the recording head to the inkchamber. It is therefore possible to prevent ink from leaking when theprinter is not in use. Also, when the ink cartridge is mounted on therecording head, negative pressure suitable for printing is maintainedbetween the recording head and the ink cartridge to ensure stableprinting.

Further, since the elasticity of the membrane valve seat ensures anairtight seal between the membrane valve seat and the valve body, thevalve function can be reliably performed irrespective of any swingingmotion or vibrations of ink in the ink chamber caused by the movement ofthe carriage, thus making it possible to maintain a pressure differencebetween the ink cartridge and the recording head irrespective of themovement of the carriage to achieve an improvement in printing quality.Preferably, the ink cartridge body (container), valve assembly and valvebody are formed of plastic.

It will thus be seen that the objects set forth above, and those madeapparent from the preceding description, are efficiently attained and,since certain changes may be made in the above constructions withoutdeparting from the spirit and scope of the invention, it is intendedthat all matter contained in the above description or shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed, and all statements of the scope of the invention which, as amatter of language, might be said to fall therebetween.

1. An ink cartridge for detachable mounting to an ink jet recordingapparatus, comprising: a container for supplying ink to the ink jetrecording apparatus, the container having a plurality of outer walls andan internal divider having an opening therethrough, the internal dividerdividing the container into an ink chamber and an ink supply chamber,the internal divider having (i) a first side facing toward the inkchamber and (ii) a second side facing toward the ink supply chamber, andan ink supply port through which ink flows to the ink jet recordingapparatus; and an elastically deformable valve seat having therein amovable central portion having a through hole having a perimeter and anouter portion surrounding the central portion, the outer portioncontacting and being fixed to a portion of the container, the valve seatbeing mounted relative to the internal divider so that the perimeter ofthe through hole contacts and is urged against, and the through hole isobstructed by, a portion of the internal divider, the obstructed throughhole being offset from the outer portion of the valve seat, wherein themounted valve seat is deformed because of contact with the portion ofthe internal divider, and wherein the valve seat only contacts theinternal divider at the through hole and the outer portion.
 2. An inkcartridge according to claim 1, wherein the portion includes a flatsection that obstructs the through hole.
 3. An ink cartridge accordingto claim 1, wherein the outer portion of the valve seat is disposedbetween the internal divider and at least one of the outer walls of thecontainer.
 4. An ink cartridge according to claim 1, wherein theperimeter of the through hole is in elastic contact with the portion sothat the opening is blocked, the valve seat thereby separating the inkchamber from the ink supply chamber and moving away from the portion ata pressure that is greater than a pressure exerted on the valve seatjust by the ink in the ink chamber.
 5. An ink cartridge according toclaim 1, wherein the perimeter of the through hole is in elastic contactwith the portion so that the opening is blocked, the valve seat therebyseparating the ink chamber from the ink supply chamber and moving awayfrom the portion when ink downstream of the valve seat establishes apressure difference larger than a predetermined pressure differencerelative to the ink in the ink chamber due to ink consumption by theink-jet recording apparatus.
 6. An ink cartridge according to claim 1,wherein the valve seat separates from the portion as a result of apressure difference between said ink chamber and said ink supply chamberdue to ink consumption by the ink jet recording head.
 7. An inkcartridge according to claim 1, wherein the through hole is disposed ata center of the valve seat.
 8. An ink cartridge according to claim 1,wherein the internal divider extends in a first direction and theopening in the internal divider is offset from the through hole in thefirst direction.
 9. A ink cartridge according to claim 1, wherein theperimeter of the through hole lies in a plane that is perpendicular toan axis of the ink supply port.
 10. An ink cartridge for detachablemounting to an ink jet recording apparatus, comprising: a container forsupplying ink to the ink jet recording apparatus, the container having aplurality of outer walls and a valve assembly wall having an openingtherethrough, the valve assembly wall dividing the container into an inkchamber and an ink supply chamber, the valve assembly wall having (i) afirst side facing toward the ink chamber and (ii) a second side facingtoward the ink supply chamber, the second side having a projectionextending toward the ink supply chamber, and an ink supply port throughwhich ink flows to the ink jet recording apparatus; and an elasticallydeformable valve seat having therein a movable central portion having athrough hole having a perimeter and an outer portion surrounding thecentral portion, the outer portion contacting and being fixed to aportion of the container, the valve seat being mounted relative to thevalve assembly wall and deformed by the projection so that the perimeterof the through hole contacts and is urged against, and the through holeis obstructed by, the projection, the obstructed through hole beingoffset from the outer portion of the valve seat, wherein the valve seatonly contacts the valve assembly wall at the through hole and the outerportion.
 11. An ink cartridge according to claim 10, wherein theprojection includes a flat portion that obstructs the through hole. 12.An ink cartridge according to claim 10, wherein the outer portion of thevalve seat is disposed between the valve assembly wall and at least oneof the outer walls of the container.
 13. An ink cartridge according toclaim 10, wherein the perimeter of the through hole is in elasticcontact with the projection so that the opening is blocked by theprojection, the valve seat thereby separating the ink chamber from theink supply chamber and moving away from the second side at a pressurethat is greater than a pressure exerted on the valve seat just by theink in the ink chamber.
 14. An ink cartridge according to claim 10,wherein the perimeter of the through hole is in elastic contact with theprojection so tat the opening is blocked by the projection, the valveseat thereby separating the ink chamber from the ink supply chamber andmoving away from the second side when ink downstream of the valve seatestablishes a pressure difference larger than a predetermined pressuredifference relative to the ink in the ink chamber due to ink consumptionby the ink-jet recording apparatus.
 15. An ink cartridge according toclaim 10, wherein the valve seat separates from the projection as aresult of a pressure difference between said ink chamber and said inksupply chamber due to ink consumption by the ink-jet recording head. 16.An ink cartridge according to claim 10, wherein the through hole isdisposed at a center of the valve seat.
 17. An ink cartridge accordingto claim 10, wherein the valve assembly wall extends in a firstdirection and the opening in the valve assembly wall is offset from thethrough hole in the first direction.
 18. An ink cartridge according toclaim 10, wherein the perimeter of the through hole lies in a plane thatis perpendicular to an axis of the ink supply port.
 19. A method ofcontrolling ink flow in an ink cartridge for detachable mounting to anink jet recording apparatus, comprising the steps of: providing acontainer for supplying ink to the ink jet recording apparatus, thecontainer having a plurality of outer walls and an internal dividerhaving an opening therethrough, the internal divider dividing thecontainer into an ink chamber and an ink supply chamber, the internaldivider having (i) a first side facing toward the ink chamber and (ii) asecond side facing toward the ink supply chamber, and an ink supply portthrough which ink flows to the ink jet recording apparatus; mounting,relative to the internal divider, an elastically deformable valve seathaving therein a movable central portion having a through hole having aperimeter and an outer portion surrounding the central portion, theouter portion contacting and being fixed to a portion of the container,so that the perimeter of the through hole contacts and is urged against,and the through hole is obstructed by, a portion of the internaldivider, the obstructed through hole being offset from the outer portionof the valve seat; and deforming the mounted valve seat through contactwith the portion of the internal dividers, wherein the valve seat onlycontacts the internal divider at the through hole and the outer portion.20. A method according to claim 19, wherein the portion includes a flatsection that obstructs the through hole.
 21. A method according to claim19, further comprising the step of securing the edge portion of thevalve seat between the internal divider and at least one of the outerwalls of the container.
 22. A method according to claim 19, wherein theperimeter of the through hole is in elastic contact with the portion sothat the opening is blocked, the valve seat thereby separating the inkchamber from the ink supply chamber and moving away from the portion ata pressure that is greater than a pressure exerted on the valve seatjust by the ink in the ink chamber.
 23. A method according to claim 19,wherein the perimeter of the through hole is in elastic contact with theportion so that the opening is blocked, the valve seat therebyseparating the ink chamber from the ink supply chamber and moving awayfrom the portion when ink downstream of the valve seat establishes apressure difference larger than a predetermined pressure differencerelative to the ink in the ink chamber due to ink consumption by theink-jet recording apparatus.
 24. A method according to claim 19, whereinthe valve seat separates from the portion as a result of a pressuredifference between the ink chamber and the ink supply chamber due to inkconsumption by the ink jet recording head.
 25. A method according toclaim 19, wherein the through hole is disposed at a center of the valveseat.
 26. A method according to claim 19, wherein the internal dividerextends in a first direction and the opening in the internal divider isoffset from the through hole in the first direction.
 27. A methodaccording to claim 19, wherein the perimeter of the through hole lies ina plane that is perpendicular to an axis of the ink supply port.
 28. Amethod of controlling ink flow in an ink cartridge for detachablemounting to an ink jet recording apparatus, comprising the steps of:providing a container for supplying ink to the ink jet recordingapparatus, the container having a plurality of outer walls and a valveassembly wall having an opening therethrough, the valve assembly walldividing the container into an ink chamber and an ink supply chamber,the valve assembly wall having (i) a first side facing toward the inkchamber and (ii) a second side facing toward the ink supply chamber, thesecond side having a projection extending toward the ink supply chamber,and an ink supply port through which ink flows to the ink jet recordingapparatus; mounting, relative to the valve assembly wall, an elasticallydeformable valve seat having therein a movable central portion having athrough hole having a perimeter and an outer portion surrounding thecentral portion, the outer portion contacting and being fixed to aportion of the container, so that the perimeter of the through holecontacts and is urged against, and the through hole is obstructed by,the projection, the obstructed through hole being offset from the outerportion of the valve seat; and deforming the valve seat owing to theposition of the projection, wherein the valve seat only contacts thevalve assembly wall at the through hole and the outer portion.
 29. Amethod according to claim 28, wherein the projection includes a flatportion that obstructs the through hole.
 30. A method according to claim28, further comprising the step of securing the outer portion of thevalve seat between the valve assembly wall and at least one of the outerwalls of the container.
 31. A method according to claim 28, wherein theperimeter of the through hole is in elastic contact with the projectionso that the opening is blocked by the projection, the valve seat therebyseparating the ink chamber from the ink supply chamber and moving awayfrom the second side at a pressure that is greater than a pressureexerted on the valve seat just by the ink in the ink chamber.
 32. Amethod according to claim 28, wherein the perimeter of the through holeis in elastic contact with the projection so that the opening is blockedby the projection, the valve seat thereby separating the ink chamberfrom the ink supply chamber and moving away from the second side whenink downstream of the valve seat establishes a pressure differencelarger than a predetermined pressure difference relative to the ink inthe ink chamber due to ink consumption by the ink-jet recordingapparatus.
 33. A method according to claim 28, wherein the valve seatseparates from the projection as a result of a pressure differencebetween the ink chamber and the ink supply chamber due to inkconsumption by the ink jet recording head.
 34. A method according toclaim 28, wherein the through hole is disposed at a center of the valveseat.
 35. A method according to claim 28, wherein the valve assemblywall extends in a first direction and the opening in the valve assemblywall is offset from the through hole in the first direction.
 36. Amethod according to claim 28, wherein the perimeter of the through holelies in a plane that is perpendicular to an axis of the ink supply port.37. An ink cartridge for detachable mounting to an ink jet recordingapparatus, comprising: a container for supplying ink to the ink jetrecording apparatus, the container having a plurality of outer walls anda valve assembly wall having an opening therethrough, the valve assemblywall dividing the container into an ink chamber and an ink supplychamber, the valve assembly wall having (i) a first side facing towardthe ink chamber and (ii) a second side facing toward the ink supplychamber, and an ink supply port through which ink flows to the ink jetrecording apparatus, the second side having an integral projection; andan elastically deformable valve seat having therein a movable centralportion having a through hole having a perimeter and an outer portionsurrounding the central portion, the outer portion contacting and beingfixed to a portion of the container, the valve seat being mountedrelative to the valve assembly wall and deformed by the integralprojection so that the perimeter of the through hole contacts and isurged against, and the through hole is obstructed by, the second side,the obstructed through hole being offset from the outer portion of thevalve seat, wherein the valve seat only contacts the valve assembly wallat the through hole and the outer portion.
 38. A method of controllingink flow in an ink cartridge for detachable mounting to an ink jetrecording apparatus, comprising the steps of: providing a container forsupplying ink to the ink jet recording apparatus, the container having aplurality of outer walls and a valve assembly wall having an openingtherethrough, the valve assembly wall dividing the container into an inkchamber and an ink supply chamber, the valve assembly wall having (i) afirst side facing toward the ink chamber and (ii) a second side facingtoward the ink supply chamber, and an ink supply port through which inkflows to the ink jet recording apparatus, the second side having anintegral projection; mounting, relative to the valve assembly wall, anelastically deformable valve seat having therein a movable centralportion having a through hole having a perimeter and an outer portionsurrounding the central portion, the outer portion contacting and beingfixed to a portion of the container, so that the perimeter of thethrough hole contacts and is urged against, and the through hole isobstructed by, the integral projection, the obstructed through holebeing offset from the outer portion of the valve seat; and deforming themounted valve seat owing to the position of the integral projection,wherein the valve seat only contacts the valve assembly wall at thethrough hole and the outer portion.
 39. An ink jet recording apparatus,comprising: a print head unit; an ink cartridge comprising; a containerfor supplying ink to the print head, the container having a plurality ofouter walls and an internal divider having an opening therethrough, theinternal divider dividing the container into an ink chamber and an inksupply chamber, the internal divider having (i) a first side facingtoward the ink chamber and (ii) a second side facing toward the inksupply chamber, and an ink supply port through which ink flows to theink jet recording apparatus; and an elastically deformable valve scathaving therein a movable central portion having a through hole having aperimeter and an outer portion surrounding the central portion, theouter portion contacting and being fixed to a portion of the container,the valve seat being mounted relative to the internal divider so thatthe perimeter of the through hole contacts and is urged against, and thethrough hole is obstructed by, a portion of the internal divider, theobstructed through hole being offset from the outer portion of the valveseat, wherein the mounted valve seat is deformed because of contact withthe portion of the internal divider, and wherein the valve seat onlycontacts the internal divider at the through hole and the outer portion,and a connecting member placing said print head unit in fluidcommunication with said ink cartridge, wherein ink in the ink cartridgecan flow through the connecting member to the print head unit.
 40. Anink jet recording apparatus according to claim 39, wherein the portionof the internal divider contacted by the through hole is flat.
 41. Anink jet recording apparatus according to claim 39, wherein the outerportion of the valve seat is held in place by the valve assembly wall.42. An ink jet recording apparatus according to claim 39, wherein theperimeter of the through hole that abuts the contact portion to blockthe opening separates from the internal divider when the valve seatexperiences a pressure that is greater than a pressure exerted on thevalve seat just by the ink in the ink chamber.
 43. An ink jet recordingapparatus according to claim 39, wherein the perimeter of the throughhole that abuts the contact portion to block the opening separates fromthe internal divider when the ink downstream of the valve seatestablishes a pressure difference larger than a predetermined pressuredifference relative to the ink in the ink chamber due to ink consumptionby the ink-jet recording apparatus.
 44. An ink jet recording apparatusaccording to claim 39, wherein the valve seat separates from theinternal divider as a result of a pressure difference between said inkchamber and said ink supply chamber due to ink consumption by the inkjet recording head.
 45. An ink jet recording apparatus according toclaim 39, wherein the contact portion projects from the internaldivider.
 46. An ink jet recording apparatus according to claim 39,wherein the valve seat is deformed so that the through hole pressesagainst the internal divider to prevent the valve seat from separatingfrom the internal divider under pressure exerted just by the ink in theink chamber.
 47. An ink jet recording apparatus according to claim 39,wherein the through hole is disposed at a center of the valve seat. 48.An ink jet recording apparatus according to claim 39, wherein theinternal divider extends in a first direction and has an opening influid communication with the ink chamber that is offset from the throughhole in the first direction.
 49. An ink jet recording apparatusaccording to claim 39, wherein the recording apparatus has plural saidcontainers.
 50. An ink jet recording apparatus, comprising: a print headunit; an ink source for supplying ink to the ink jet recordingapparatus, the ink source including; an ink cartridge comprising; acontainer for supplying ink to the print head, the container having aplurality of outer walls and an internal divider having an openingtherethrough, the internal divider dividing the container into an inkchamber and an ink supply chamber, the internal divider having (i) afirst side facing toward the ink chamber and (ii) a second side facingtoward the ink supply chamber, and an ink supply port through which inkflows to the ink jet recording apparatus; and an elastically deformablevalve seat having therein a movable central portion having a throughhole having a perimeter and an outer portion surrounding the centralportion, the outer portion contacting and being fixed to a portion ofthe container, the valve seat being mounted relative to the internaldivider so that the perimeter of the through hole contacts and is urgedagainst, and the through hole is obstructed by, a portion of theinternal divider, the obstructed through hole being offset from theouter portion of the valve seat, wherein the mounted valve seat isdeformed because of contact with the portion of the internal divider,and wherein the valve seat only contacts the internal divider at thethrough hole and the outer portion; and a connecting member placing saidprint head unit in fluid communication with said ink cartridge, whereinink in the container can flow through the connecting member to the printhead unit.
 51. An ink jet recording apparatus according to claim 50,wherein the recording apparatus has plural said ink cartridges.
 52. Anink jet recording apparatus, comprising: a print head unit; an inksupply; an ink cartridge mounted in the ink jet recording apparatus, theink cartridge comprising; a container for supplying ink to the printhead, the container having a plurality of outer walls and an internaldivider having an opening therethrough, the internal divider dividingthe container into an ink chamber and an ink supply chamber, theinternal divider having (i) a first side facing toward the ink chamberand (ii) a second side facing toward the ink supply chamber, and an inksupply port through which ink flows to the ink jet recording apparatus;and an elastically deformable valve seat having therein a movablecentral portion having a through hole having a perimeter and an outerportion surrounding the central portion, the outer portion contactingand being fixed to a portion of the container, the valve seat beingmounted relative to the internal divider so that the perimeter of thethrough hole contacts and is urged against, and the through hole isobstructed by, a portion of the internal divider, the obstructed throughhole being offset from the outer portion of the valve seat, wherein themounted valve seat is deformed because of contact with the portion ofthe internal divider, and wherein the valve seat only contacts theinternal divider at the through hole and the outer portion; and aconnecting member placing said print head unit in fluid communicationwith said enclosure, wherein ink in the container can flow through theconnecting member to the print head unit.
 53. An ink jet recordingapparatus according to claim 52, wherein the recording apparatus hasplural said enclosures.